Has anyone got hands-on with the Sony VAIO Tap 20?

If you haven't seen it, it's a 20" Windows 8 device that seems to be primarily a desktop, but with a form factor designed to unplug and use like a giant tablet. It's not portable enough to be a true tablet (size, weight and battery life under three hours) and also has some limitations as a desktop (no optical device, limited connection options and perhaps a little under-spec'ed). But as everyone in my family already has an iPad and/or a smartphone, the existing desktop doesn't see much action these days. The Tap looks like an interesting idea but may be too much of a compromise on both fronts and therefore struggling to define it's target audience.

I googled a few reviews and they are mixed (from 4.5 down to 2 out of 5) although there is more praise for a higher spec'ed model Sony aren't selling here (yet). So I just wondered whether anyone had played with one of these yet, and if so, what you thought?